My 6 year old son, doesn't like any food that is green....spinach, broccoli,peas, beans, celery... I find it very hard to disguise these vegetables simply because of their colour. Any ideas or kid friendly recipes, that may work?

Why go to the effort of disguising green vegetables? Broccoli is a good source of vitamin A, for example. But carrots are even better, and sweet potatoes better again. And there's potatoes, corn and tomatoes. Between those and fruits, grains, nuts, and non-green legumes, it's all pretty much covered.

If YOU want greens, eat 'em. There are plenty of other things for him, without disguises.

__________________"Kitchen duty is awarded only to those of manifest excellence..." - The Master, Dogen

Try some yellow (wax) beans. They taste just like green.
Cauliflower is white easy to work with...

For a fun twist on this issue - you might try a plate of raw carrots, cauliflower, cukes, yellow squash rounds and any other non green veggie can can find and some ranch style dip in 3 or 4 tiny bowls. Have him add a drop of food color to each bowl (including green) and then go to town on the veggies and colored dips.

Another thing to do, and 6 isn't too young to start, is get him involved in the food making process. Even if it's just to tear up lettuce leaves for salad or rinse the head of broccoli, anything that will get him involved can help him to enjoy those vegetables. Our boys loved tearing the lettuce for salad. Another thing is to try preparing them in a different way. My wife doesn't care for cooked spinach, but she loves it raw in a salad. Easy solution.
But I think the best thing you can try is to get him involved in the process.

Oh, a couple other things I just thought of:
Cheese sauce! Is there any green veg that cheese sauce doesn't fix?
Also, try undercooking the veg just a little bit. Stir fry, or a light steam, so the veg is still crisp tender can make a big difference. Again, my wife thought she didn't care for certain vegetables until I made them for her leaving them crisp tender instead of soft. She figured out it was the soft and mooshy texture of the veg she didn't care for and not the veg itself.

My suggestion would be not to disguise veggies. My younger son was super picky, still is and likes few and far in between veggies. Actually he would eat junk and survive on it if I let him.

Try to incorporate veggies in ways that he can eat them and enjoy them. So pasta is a good thing to put them in. You can chop them finely and saute them before adding the tomato sauce.

You can make fried rice if he likes that, my son did so I would add carrots, green beans, bell pepper to it and he would eat that. It would also have chicken so he did not fuss much.

I would make pizza and let him pick his veggie topping. I also made black bean dip with lots of chopped veggies in it (bell peppers, tomatoes, avacado) and then I would serve that in a taco shell and my kids would eat it up. I would have ground turkey with it as well so it was a layered taco and they always insisted they loved the bean and veggie dip on their taco.

I also like to make sandwiches with roasted veggies. I made it with roasted eggplant, bell peppers etc and when you toast them in a panini press with cheese it is great and they would eat it up in no time.

Lastly, my policy now is eat it or go hungry. It works because my kids are older now (11 and 14) and they know mom means business.